I recently clamped my amp for my two BTL N2s, impedance started at .7 (no box rise ftw) and ended up at 4.5 ohms!! That's a huge jump. Dr. Boom also has bad impedance rise, he's only getting 5k out of his 6 SAZ-3500s. Maybe it's just coincidence but I was comparing the BTLs specs to other subwoofers specs and BTLs have a much lower Qes that any other I seen. They still get extremely loud on low power so maybe they are very efficient due to low Qes. Can anyone chime in?

Oh, box for mine is 4.2 cubes, 33hz, single 6" aero. Dr Booms, dont know volume, but tuned to 33hz also.

Just happened to read around on a topic about impedance rise at different frequencies... Well, nevermind I guess.

Dr Boom needs a much more efficient enclosure.

i dont know the techy techy side of it but from what i've seen, neos typically have higher rise than ferrite.

I don't know if that's always a fact but there are videos online of a single neo running off an 11,000w on a single 3" coil and never fried.

You can look at it two ways-

Neos can be seen as efficient because of the ability to draw less power for the same potential output

or... innefficient because of the additional power they can handle to really get them going crazy..

I tend to look at them from the first point of view.

dont worry about it..

I remember one time i had a single 15 in 8cuft wired at 0.7 and rose to 4.2ohms, just 2hz above tuning on a 1500w amp long time ago on ferrite motor.

Seems like you could use more port area, would less port area cause more impedance rise???

Edited June 13, 201114 yr by trod2902

Dr Boom needs a much more efficient enclosure.

LOL, if you sat in it, oh lord.

And Dr. Boom has the ferrites. It's hard to tell, I wonder what Qes actually affects.

Seems like you could use more port area, would less port area cause more impedance rise???

Yes, less port area causes higher rise. Smaller enclosure also reduces impedance rise.

Take a read on here, http://www.bcae1.com/spboxad2.htm

May not be an answer but it deals somewhat with the subject.

Dr Boom needs a much more efficient enclosure.

Have you clamped your amps and calculated your imp rise? I think you'll be surprised when you do it.